Field of the Invention
The present invention relates to a yield monitoring system and in particular to a load cell impact plate intercepting a portion of clean grain flow within a harvester.
Description of the Prior Art
Yield monitoring systems are commonly used for grain combines and other harvesters to determine the yield of the crop being harvested. Such systems typically use a small impact plate inserted downstream in the harvester and the clean grain flow path. The impact plate typically has an area of approximately four inches by six inches and deflects a portion of the flow. The impact of the flow being deflected places a load on the impact plate, which is transmitted to a load cell. The force measured by the load cell is calibrated so that the flow and therefore the yield can be calculated.
Although such yield measurement systems may be satisfactory for many applications, there are problems. The small impact plate may not provide an accurate measurement of the flow. For certain types of crops in which the fruit or vegetables are relatively large, such as for example ear corn, potatoes, citrus and similar sized crops, such systems are more prone to error and may not provide satisfactory results. The large objects being transported, such as ears of corn, compared to small articles such as granular grains, may impact with a greater force. However, depending on where the particular ears strike the impact plate, the force may not be accurately conveyed to and sensed by the load cell. Moreover, the flow path in an ear corn or other harvester for relatively large crops is larger than for other types of grain harvesters and a relatively small impact plate may not intercept a sufficient percentage of the crop flow and may not therefore accurately reflect the actual flow. Moreover, the direct mounting of the load cell to the impact plate results in inaccuracies should the ears of corn strike an edge of the plate or otherwise impact the plate at varied angles, which may not press the plate squarely against the load cell.
It can therefore be seen then that a new and improved yield monitoring system is needed that accurately measures the harvest yield of grains including larger crops such as ear corn to eliminate false readings obtained in prior art systems. Such a system should intercept a sufficiently large percentage of the clean grain flow to provide accurate flow measurement. Moreover, the impact plate should be mounted in such a manner that the impact force will always be accurately transmitted to the load cell from strikes on all areas of the strike plate. Such a mounting system should also be reliable and should have a long operating life. The present invention addresses these as well as other problems associated with yield monitoring systems.